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Notes
- 1.
A planetary companion was found around the primary star Gamma-1 Leonis in 2009. There is also unsubstantiated evidence of a further companion.
- 2.
The least luminous stars that are currently known are located in the globular star cluster NGC 6397, also known as Caldwell 86. It is incidentally, the second closest globular cluster to us.
- 3.
Interestingly, recent work has shown that Denebola shows a strong infrared excess, which means that there is a circumstellar debris disk of cool dust in orbit around it. Observations with the Herschel Space Observatory have provided images, showing the disk at a radius of 39 Astronomical Units from the star. Was this the cause of the discrepancy of magnitude measurements one wonders?
- 4.
In 2009 it was suggested that the fluctuations observed for the star could be due to the presence of an evaporating extrasolar planet. This however has yet to be confirmed.
- 5.
There are in fact many meteor shower streams that occur during what is known as the Virginid Complex. These include the Alpha Virginids, Gamma Virginids, Eta Virginids, Theta Virginids, Iota Virginids, Lambda Virginids, Mu Virginids, Pi Virginids, and Psi Virginids, and March Virginids. Most emanate from the constellation Virgo between February and May.
- 6.
We know now that there are at least three confirmed extrasolar planets in orbit around 47 Ursae Majoris. All three have a mass greater than that of Jupiter.
- 7.
The meteor shower lasts from April 16 to April 26 each year, with a peak that is now reckoned to be around April 22 each year.
- 8.
NGC 3115 is now classified as a Lenticular galaxy, classification S0. It is a type of galaxy that has a disk and a central bulge but lacks a visible spiral pattern.
- 9.
Due to the vast number of stars in the cluster as well as its chemical composition, and the ages of its stars, it has been suggested that Omega Centuari is in fact the core of a smaller galaxy that has undergone disruption due to the gravitational influence of the Milky Way. An event that is often referred to as Galactic Cannibalism!
- 10.
The distance to Centaurus A is the subject of much debate, and current values seem to depend on which method of distance determination is used.—Classical Cepheids, Mira variables, Type II Cepheids, and planetary nebulae—it ranges from 10 million to 16 million light years.
- 11.
Research suggests it is around 14 million years old.
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Inglis, M. (2015). April. In: Inglis, M. (eds) Patrick Moore’s Observer’s Year: 366 Nights of the Universe. The Patrick Moore Practical Astronomy Series. Springer, Cham. https://doi.org/10.1007/978-3-319-18678-8_4
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